In the United States, the Federal Communications Commission has recently made radio spectrum in the 3.55-3.7 Gigahertz range available for implementation of the Citizens Broadband Radio Service (CBRS). CBRS spectrum is allocated in a three tiered arraignment. The highest priority tier is the Incumbent Access tier, which generally includes the legacy users of the CBRS band (e.g. federal government users). The next tier is the Priority Access tier in which spectrum is allocated in a competitive bidding process. The third, and lowest priority, tier is the General Authorized Access tier.
Use of spectrum in the CBRS band is authorized via a Spectrum Access System (SAS). When a network infrastructure operator wishes to use spectrum in the CBRS band, an authorization request is sent to the SAS. The SAS then decides, based on various complex factors, if spectrum will be allocated to the requestor. For purposes of this description, the general rule followed by the SAS is if the requested spectrum is not currently being used by a higher tiered user, then the spectrum will be allocated.
For example, a General Authorized Access network operator may request a portion of the CBRS spectrum from the SAS. So long as that portion of the spectrum is not in use by an Incumbent Access tier or Priority Access tier operator, the spectrum will be granted to the requestor. For completeness sake, it should be noted that there are other factors considered (e.g. RF interference) by the SAS when making allocation decisions, but those factors are not of particular relevance to the present disclosure.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.